1. Field of the Invention
The present invention relates to a probe card with a contact probe used in measuring and evaluating the electrical characteristics of a semiconductor device.
2. Background Art
During measurement and evaluation of the electrical characteristics of a semiconductor device, a contact probe provided to a probe card is used to electrically connect a connection pad provided on a surface of the semiconductor device and an external measuring unit and the like. Generally, the contact probe is made of a material harder than that of the connection pad. So, pressure applied by pressing the contact probe against the connection pad generates a scratch or an indentation in a surface of the connection pad. If such damage is increased by application of excessive pressure, the semiconductor device may be broken partially to generate serious failure. Even if the semiconductor device is not broken, a subsequent bonding step may be affected adversely. According to a conventional testing method (disclosed in Japanese Patent Application Laid-Open No. 2006-329871, for example), the aforementioned indentation is avoided by using a conductive liquid substance as an intermediary.
A tip end of the contact probe generally has a projecting shape in the form of a needle. So, during measurement and evaluation of the electrical characteristics of a semiconductor device with the contact probe, a current density increases steeply at the tip end of the contact probe when a current is applied. The steep increase of the current density generates sudden heat generation in a surface and its vicinity of the semiconductor device including a connection pad having contacted the contact probe, thereby generating damage on the connection pad or partial breakdown of the semiconductor device. According to conventional technique (disclosed in Japanese Patent Application Laid-Open No. 5-109847 (1993), for example), such heat generation is avoided by cooling with a fluid.
However, measurement and evaluation of Japanese Patent Application Laid-Open No. 2006-329871 using a conductive liquid substance as an intermediary involves application of the conductive liquid substance on each connection pad before the measurement and evaluation, and removal of the conductive liquid substance after the measurement and evaluation. This becomes an obstacle to cost reduction and facilitation of manufacturing steps.
Further, use of a cooling unit to cool a heating element in Japanese Patent Application Laid-Open No. 5-109847 involves modification of a chuck stage of a measuring and evaluating device. This generates a problem of extremely high cost, especially if a plurality of measuring and evaluating devices is provided.